|
|
|
| EVOLUTION CHARACTERISTICS OF MESO-CRACKS OF GAS-FILLED RAW COAL UNDER COMPRESSION-SHEAR STRESS |
| XU Jiang1，2，SU Xiaopeng1，2，CHENG Lichao1，2，WANG Lei1，2，LIU Jing1，2，FENG Dan1，2 |
(1. State Key Laboratory of Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400044，China；
2. State and Local Joint Engineering Laboratory of Methane Drainage in Complex Coal Gas Seam，
Chongqing University，Chongqing 400044，China) |
|
|
|
|
Abstract Using self-developed meso-shear test equipment for coal and rock containing gas，tests of raw coal containing gas under compression-shear stress were carried out to study the meso-cracks? dynamic evolution. The formation of gas migration pathways is described；and the factors influencing meso-morphological characteristics of cracks are analyzed. The results show that the evolution of cracks provides pathways for gas migration in coal continuously. Coal surface crushes and then drop as the gas pressure and compression-shear stress on coal simultaneously. The fractured zone has more initiations of cracks conversely. Both the horizontal original cracks and hard granules have effects on the meso-cracks；cracks initiate more easily when encounter the original cracks；then the newly formed cracks and the original cracks together make the composition of an H-shaped one locally. There is also always a dislocation for newly formed cracks subjected to the original cracks. The evolution directions of cracks change because of the existence of hard granules which are always bypassed，the bifurcation angles range from 10°–100° which shows obvious discreteness and meso-cracks are formed by tension and shear together. There are more pathways for gas migration as the existence of original cracks and hard granules. Both the fracture distribution rate and coal crushing extent increase as the normal stress increases and the effect of initial damages and hard granules.
|
|
Received: 17 June 2013
|
|
|
|
| [1] AMMOSOV I I，EREMIN I V. Fracturing in coal[M]. Moscow：IZDAT Publishers，1963：1–112.
[2] SMYTH M，BUCKLEY M J. Statistical analysis of the microlithotype sequences in the Bulli seam，Australla，and relevance to permeability for coal gas[J]. International Journal of Coal Geology，1993，22(3)：167–187.
[3] ZHOU H W，LIU J F，LI J，et al. Numerical simulation of gas flow process in mining-induced crack network[J]. International Journal of Mining Science and Technology，2012，22(6)：793–799.
[4] WEI X J，GAO M Z，LV Y C，et al. Evolution of a mining induced fracture network in the overburden strata of an inclined coal seam[J]. International Journal of Mining Science and Technology，2012，22(6)：779–783.
[5] 谢和平，于广明，杨 伦，等. 采动岩体分形裂隙网络研究[J]. 岩石力学与工程学报，1999，18(2)：147–151.(XIE Heping，YU Guangming，YANG Lun，et al. Research on the fractal effects of crack network in overburden rock stratum[J]. Chinese Journal of Rock Mechanics and Engineering，1999，18(2)：147–151.(in Chinese))
[6] 张向东，徐峥嵘，苏仲杰，等. 采动岩体分形裂隙网络计算机模拟研究[J]. 岩石力学与工程学报，2001，20(6)：809–812.(ZHANG Xiangdong，XU Zhengrong，SU Zhongjie，et al. Research of the imitation about the fractal crack in overburden rock stratum by computer[J]. Chinese Journal of Rock Mechanics and Engineering，2001，20(6)：809–812.(in Chinese))
[7] 许 江，李 贺，鲜学福，等. 对单轴应力状态下砂岩微观断裂发展全过程的实验研究[J]. 力学与实践，1986，8(4)：16–20.(XU Jiang，LI He，XIAN Xuefu，et al. Meso-mechanical experiment of micro fracturing progress of sandstone under uniaxial stress condition[J]. Mechanics in Engineering，1986，8(4)：16–20.(in Chinese))
[8] 尚嘉兰，孔常静，李廷芥，等. 岩石细观损伤破坏的观测研究[J].实验力学，1999，14(3)：373–383.(SHANG Jialan，KONG Changjing，LI Tingjie，et al. Observation and study on meso-damage and fracture of rock[J]. Journal of Experimental Mechanics，1999，14(3)：373–383.(in Chinese))
[9] ZHU Z D，NI X H，WANG W，et al. Dynamic experimental study on rock meso-cracks growth by digital image processing technique[J]. Journal of Central South University of Technology，2008，15(Supp.2)：114–120.
[10] WU X Y，BAUD P，WONG T. Micromechanics of compressive failure and spatial evolution of anisotropic damage in Darley Dale sandstone[J]. International Journal of Rock Mechanics and Mining Sciences，2000，37(1)：143–160.
[11] 刘冬梅，蔡美峰，周玉斌. 岩石细观损伤演化与宏观变形响应关联研究[J]. 中国钨业，2006，21(4)：16–19.(LIU Dongmei，CAI Meifeng，ZHOU Yubin. Study on the relationship between meso-damage development and macro deformation of rock under uniaxial compression[J]. China Tungsten Industry，2006，21(4)：16–19.(in Chinese))
[12] 葛修润，任建喜，蒲毅彬，等. 岩石细观损伤扩展规律的CT实时试验[J]. 中国科学：E辑，2000，30(2)：104–111.(GE Xiurun，REN Jianxi，PU Yibin，et al. Real-time CT test on the meso-damage development law of rock[J]. Science in China：Series E，2000，30(2)：104–111.(in Chinese))
[13] 任建喜，葛修润，蒲毅彬，等. 岩石破坏全过程的CT细观损伤演化机制动态分析[J]. 西安公路交通大学学报，2000，20(2)：12–15. (REN Jianxi，GE Xiurun，PU Yibin，et al. CT real-time analysis of meso-damage propagation law of the whole process of rock failure[J]. Journal of Xi?an Highway University，2000，20(2)：12–15.(in Chinese))
[14] 李 炼，徐 钺，李启光，等. 花岗岩板渐进破坏过程的微观研究[J]. 岩石力学与工程学报，2002，21(7)：940–947.(LI Lian，XU Yue，LI Qiguang，et al. Progressive cracking of granite plate under uniaxial compression[J]. Chinese Journal of Rock Mechanics and Engineering，2002，21(7)：940–947.(in Chinese))
[15] PENG S J，XU J，YIN G Z，et al. Spatial-temporal evolution of gas migration pathways in coal during shear loading[J]. International Journal of Mining Science and Technology，2012，22(6)：769–773.
[16] 滕桂荣，谭云亮，高 明. 基于Lattice Boltzmann方法对裂隙煤体中瓦斯运移规律的模拟研究[J]. 岩石力学与工程学报，2007，26(增1)：3 503–3 508.(TENG Guirong，TAN Yunliang，GAO Ming. Simulation of gas seepage in fissured coal based on Lattice Bolizmann method[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(Supp.1)：3 503–3 508.(in Chinese))
[17] 徐 涛，杨天鸿，唐春安，等. 含瓦斯煤岩破裂过程固气耦合数值模拟[J] .东北大学学报：自然科学版，2005，26(3)：293–296.(XU Tao，YANG Tianhong，TANG Chun′an，et al. Numerical simulation on coupled solid-gas flow in failure process of gaseous coal and rock[J]. Journal of Northestern University：Natural Science，2005，26(3)：293–296.(in Chinese))
[18] 许 江，彭守建，尹光志，等. 含瓦斯煤岩细观剪切试验装置的研制及应用[J]. 岩石力学与工程学报，2011，30(4)：677–685.(XU Jang，PENG Shoujian，YIN Gangzhi，et al. Development of meso-shear test equipment for coal rock containing gas and its application[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(4)：677–685. (in Chinese))
[19] 许 江，程立朝，谭皓月，等. 原生裂纹对煤岩剪切破坏宏细观演化规律的影响研究[J]. 岩石力学与工程学报，2013，32(1)：677–685.(XU Jang，CHENG Lichao，TAN Haoyue，et al. Effects of original cracks on macro-meso evolution law of raw coal shear failure[J]. Chinese Journal of Rock Mechanics and Engineering，2013，32(1)：677–685.(in Chinese))
[20] 黄明利，唐春安. 非均匀因素对I型裂纹扩展、相互作用影响的数值分析[J]. 岩石力学与工程学报，2002，21(8)：1 111–1 114.(HANG Mingli，TANG Chun?an. Effect of heterogeneity on propagation and interaction of type I cracks[J]. Chinese Journal of Rock Mechanics and Engineering，2002，21(8)：1 111–1 114.(in Chinese))
[21] 聂百胜，段三明. 煤吸附瓦斯的本质[J]. 太原理工大学学报，1998，29(4)：417–421.(NIE Baisheng，DUAN Sanming. The adsorption essence of gas on coal surface[J]. Journal of Taiyuan University of Technology，1998，29(4)：417–421.(in Chinese))
[22] 许 江，陆丽丰，杨红伟，等. 剪切荷载作用下砂岩细观开裂扩展演化特征研究[J]. 岩石力学与工程学报，2011，30(5)：944–950. (XU Jiang，LU Lifeng，YANG Hongwei，et al. Study of evolution law of microfracturing process of sandstone under shear load[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(5)：944–950. (in Chinese))
[23] 芮勇勤，唐春安. 岩石剪切破坏过程的RFPA2D数值模拟[J]. 岩石力学与工程学报，2002，21(3)：364–368.(RUI Yongqin，TANG Chun?an. Numerical simulation on failure process of rock sample with RFPA2D code under direct shear test[J]. Chinese Journal of Rock Mechanics and Engineering，2002，21(3)：364–368.(in Chinese)) |
|
|
|
2014, Vol. 33 
